The proposed recognition of same-sex marriage in the U.K. will have major consequences for society and children and represents a "grotesque" subversion of human rights, Cardinal Keith P. O'Brien of St. Andrews and Edinburgh says.

"Redefining marriage will have huge implications for what is taught in our schools, and for wider society. It will redefine society since the institution of marriage is one of the fundamental building blocks upon which society is built. The repercussions of enacting same sex marriage into law will be immense," the cardinal wrote in a March 4 Sunday Telegraph commentary.

Recognizing same-sex marriage would "eliminate entirely" from law the idea of a mother and a father for every child, warned Britain's most senior cleric.

"It would create a society which deliberately chooses to deprive a child of either a mother or a father," he said, emphasizing children's right to have parents of both sexes. He added that there is "overwhelming" evidence that these marital unions benefit children the best.

The Universal Declaration on Human Rights, he noted, defines marriage as a relationship between a man and a woman. It recognizes the family as "the natural and fundamental group unit of society" that is "entitled to protection by society and the State."

"This universal truth is so self-evident that it shouldn't need to be repeated," he continued, adding that politicians' proposals to redefine marriage represent "a grotesque subversion of a universally accepted human right."

The cardinal said it is "staggeringly arrogant" for a government to claim the moral authority to "dismantle the universally understood meaning of marriage."

He warned about the practical consequences of such a redefinition, questioning what will happen to a teacher who wants to tell pupils that marriage can only mean the union of a man and a woman.

"Will that teacher's right to hold and teach this view be respected or will it be removed? Will both teacher and pupils in simply become the next victims of the tyranny of tolerance, heretics whose dissent from state-imposed orthodoxy must be crushed at all costs?"

He cited the example of education in the U.S. state of Massachusetts, which quickly moved to normalize homosexual advocacy after the state recognized same-sex marriage there.

U.K. laws presently recognize civil partnerships, which give same-sex couples a variety of legal protections.

Cardinal O'Brien recalled that during the debate over these partnerships, supporters "were at pains to point out that they didn't want marriage, accepting that marriage had only ever meant the legal union of a man and a woman."

Those who did not favor civil partnerships warned that same-sex marriage would be demanded, too, the cardinal noted.

"We were accused of scaremongering then, yet exactly such demands are upon us now."